1. Field of the Invention
The present invention relates to an improved horizontal heater treater for the treatment of crude oil to remove gas, water and basic sediment and water (BS&W) from the oil.
2. Description of the Related Art
Heater treaters for the treatment of oil are well known in the petroleum industry. Crude oil pumped from an oil well will contain gas, water and sediment. Before the crude can be refined, the water and sediment must be removed. Also, the gas must be separated from the liquid oil so that each may be further refined and treated.
Heater treaters, as their name implies, employ heat to lower the viscosity of the crude oil so the gas, water, sediment and oil emulsions—can be separated from each other. The heater treater functions to remove the basic sediment and water, commonly referred to as the BS&W, from the other two components and to separate the oil from the gas.
However, several problems exist within the technology employed in current heater treaters that makes them less efficient than desired.
One problem with some heater treaters is that they are vertical instead of horizontal. By employing a horizontal vessel with an inlet on one end of the vessel and outlets on an opposite end of the vessel, this allows for longer residence time in the vessel and thus results in better separation.
Another problem with some heater treaters is that they do not provide means for initially separating water from the oil and preventing reentrainment of the water in the oil prior to heating. Because water is more heat conductive than oil and because heating the water does not result in improved separation like heating of the oil, failure to initially separate water or failure to prevent reentrainment of water in the oil prior to heating results in much higher heating costs than necessary. This makes the units less efficient and more costly to operate.
An additional problem with some heater treaters is their design is not conducive to allowing efficient removal of solids from the vessel. This can lead to silting in of the vessel to the point that the vessel must be taken out of service to remove the sediment that has accumulated in the bottom.
Still a further problem with some heater treaters is they are not designed for easy access to the interior of the units so that the units can be cleaned out or otherwise serviced.
A further problem with some heater treaters is they do not have good control of the level of the oil-water interface which can result in poor separation, particularly during slug conditions.
Another problem with some heater treaters is that they depend on gravity alone to accomplish the separation of the components following heating of the mixture to be separated.
An additional problem with some heater treaters is the heater tubes are not oriented to provide maximum contact with the surrounding oil, thereby reducing the heat transfer from the heater tubes to the oil and making the unit less efficient.
A further problem with some heater treaters is they generally do not have a means for introducing the incoming fluid into the vessel in such a way that free gas is removed from the incoming stream as it enters the vessel.
Still a further problem with some heater treaters is they introduce the water and oil mixture at the top of the heating portion of the vessel instead of at the bottom of the vessel which forces the water to migrate through the oil layer and keeping it entrained in the oil for a longer period of time.
Another problem with some heater treaters is they do not employ vortex breakers on the exits of the unit.
The present invention addresses these problems and provides a reliable, easily serviceable, and efficient unit for treating petroleum mixtures.
Further, the present invention has less corrosion, less chance of fire, and requires less fuel to operate. Also, the present invention controls nitrous oxide production. Additionally, the design has full diameter openings and all of the internal components with the exception of the oil spillover weir and inlet diverter are bolted in place so that they can be removed or replaced as needed.